Water-in-oil emulsion, composition comprising such an emulsion, and use thereof

ABSTRACT

The present invention relates to a stable water-in-oil emulsion for cosmetic, pharmaceutical or hygiene use, comprising an aqueous phase and a fatty phase comprising a silicone oil, characterized in that it comprises an emulsifying system comprising at least one α,ω-substituted oxyalkylenated silicone of formula (I):                    
     in which: R=—(CH 2 ) p O—(C 2 H 4 O) x (C 3 H 6 O) y R 1    
     where: 
     R 1  represents H, CH 3  or CH 2 CH 3 , 
     p is an integer ranging from 1 to 5, x ranges from 1 to 100 and y ranges from 1 to 50, 
     it being possible for the units (C 2 H 4 O) and (C 3 H 6 O) to be distributed randomly or in blocks, 
     the R 2  radicals represent a C 1 -C 3  alkyl radical or a phenyl radical, 
       5 ≦m≦ 300,    
     and a co-surfactant chosen from the family of glycol mono- and/or diesters and glyceryl mono-, di- and/or triesters, and mixtures thereof. The invention also relates to a composition comprising the above emulsion, and to its applications in the cosmetics, pharmaceutical, dermatological or hygiene fields.

The present invention relates to water-in-oil (W/O) emulsions, tocompositions for cosmetic, pharmaceutical, hygiene or dermatologicaluse, comprising such an emulsion, as well as to their use in thecosmetic, pharmaceutical, dermatological and/or hygiene fields.

These compositions may constitute care products for the skin, includingthe scalp, and/or make-up products for the skin, mucous membranes (theinside of the eyelids), semi-mucous membranes (lips), keratin fibres(hair, eyelashes, nails) or alternatively make-up products for the body.

Make-up compositions, in particular foundations, are generally in theform of a more or less fluid cream comprising fatty substances such asoils and a particulate phase generally composed of fillers and pigments.

It is generally sought to introduce into the fatty phase compounds suchas silicones, which provide softness and fluidity. However, it is knownthat as the silicone oil content increases, it is more difficult toobtain a stable W/O emulsion, not only over time but also when it issubjected to large variations in temperature. In fact, the fluidity ofthe formula can be the cause of phenomena of instability over time, suchas the release of oil at the surface, sedimentation of the pigments,thickening, etc.

With the aim of reducing these phenomena, it has been proposed in U.S.Pat. No. 4,698,178 to use a new class of silicone surfactants associatedwith polyols for the low temperatures, and with electrolytes or withmetal soaps for the high temperatures.

The improvement in the stability of W/O emulsions has also been studiedin patent application EP 331,833, which describes the use ofoxyalkylenated silicones combined with water-swellable inorganic clays,and in patent application EP-A-612,517, which recommends the use of acombination of a silicone containing oxyalkylene groups and pendantalkyls with a gelling and/or thickening agent.

Nevertheless, when these compositions are applied to the skin, mucousmembranes or semi-mucous membranes, they have the disadvantage oftransferring to another surface. This means that the composition, onceapplied, is liable to be deposited, at least partly, on certain supportswith which it is placed in contact, such as, for example, a glass, anitem of clothing or the skin.

Once deposited, the said composition leaves a trace on the said support.This thus results in mediocre staying power of the composition on theskin or the mucous membranes, thus making it necessary to regularlyrenew its application.

Moreover, the appearance of unacceptable traces of the composition oncertain items of clothing, and in particular on shirt collars, candiscourage women from using this type of make-up.

Another disadvantage of these compositions lies in the problem ofmigration. Specifically, it has been found that certain compositionshave a tendency to diffuse or migrate inside the fine lines and/orwrinkles on the skin, in the case of foundations; in the fine linessurrounding the lips, in the case of lipsticks; and in the folds of theeyelids, in the case of eyeshadows. The appearance of lines in themake-up, generated by the movements of the eyelids, has also been found,in particular in the case of eyeshadows. All of these phenomena generatea displeasing effect which, needless to say, it is desired to avoid.

The aim of the present invention is to provide a water-in-oil emulsionwhich has good stability, while at the same time retaining good cosmeticproperties. In particular, it is desired to have available a stablewater-in-oil emulsion which does not transfer after it has been used, inparticular on the skin.

It has now been discovered, surprisingly and unexpectedly, that by usinga specific emulsifying system, it is possible to obtain W/O emulsionswhich are not only stable over time, but are also stable with respect tovariations in temperature, and which also show excellent cosmeticproperties, as well as good resistance to transfer.

A subject of the present invention is thus a water-in-oil emulsion,comprising an aqueous phase and a fatty phase comprising a silicone oil,characterized in that it comprises an emulsifying system comprising atleast one α,ω-substituted oxyalkylenated silicone of formula (I):

in which: R=—(CH₂)_(p)O—(C₂H₄O)_(x)(C₃H₆O)_(y)R¹

where: R¹ represents H, CH₃ or CH₂CH₃,

p is an integer ranging from 1 to 5, x ranges from 1 to 100 and y rangesfrom 1 to 50,

it being possible for the units (C₂H₄O) and (C₃H₆O) to be distributedrandomly or in blocks,

the R² radicals represent a C₁-C₃ alkyl radical or a phenyl radical,

5≦m≦300,

and a co-surfactant chosen from the family of glycol mono- and/ordiesters and glyceryl mono-, di- and/or triesters, and mixtures thereof.

For the purposes of the invention, the term “co-surfactant” refers to anamphiphilic compound, i.e. a compound comprising both a lipophilic part(apolar part) and a hydrophilic part (polar part) and which can beadsorbed onto a surface or an interface.

Another subject of the invention relates to a composition, in particulara cosmetic, dermatological, pharmaceutical or hygiene composition,comprising an emulsion as defined above.

The invention also relates to a non-therapeutic treatment process forthe skin and/or keratin fibres, in particular a make-up process, whichcomprises applying an emulsion and/or a composition as defined above tothe skin and/or to the keratin fibres.

Another subject of the invention relates to the use of an emulsifyingsystem as defined above, for preventing, limiting and/or reducing thetransfer and/or migration of a cosmetic, dermatological, hygiene and/orpharmaceutical composition, in particular a make-up and/or carecomposition for the skin, mucous membranes or semi-mucous membranes.

Another subject of the invention relates to a process for limiting,reducing and/or preventing the transfer of a cosmetic, dermatological,hygiene and/or pharmaceutical composition, in particular a make-upand/or care composition for the skin, mucous membranes, semi-mucousmembranes and/or keratin fibres, this process comprises introducing anemulsifying system as described above into the said composition.

The W/O emulsion according to the invention fully satisfies thestability standards, i.e.:

resistance to the centrifugation test at 4000 rpm for 1 hour,

resistance to aging for 2 months at room temperature (25° C.) as well asat 45° C.,

resistance to 8 successive cycles of 8 hours each, where thetemperatures of each cycle range from −20° C. to +20° C.

The emulsion according to the invention satisfies the followingcriteria:

it has and retains over the course of these tests a uniform and stablemacroscopic and microscopic appearance (finely dispersed globules,absence of release) and

its viscosity is constant over time.

The emulsion according to the invention also has very good resistance totransfer. Furthermore, the emulsion applied to the skin has theadvantage of not migrating or diffusing in the folds of the skin inparticular on the eyelids and/or the wrinkles on the face, in particularon the lips and on the eyes, and the contours of these areas (crow'sfeet).

It has been found that the emulsion used according to the inventionapplies and spreads easily and homogeneously, without leaving a greasysensation, and has good cosmetic properties. The film obtained also hasa light texture and remains comfortable to wear throughout the day.

Moreover, it is possible to add other adjuvants to the emulsionaccording to the invention, such as oils and/or powders (pigments and/orfillers), while at the same time retaining a stable emulsion. Theemulsion is thus compatible with a large number of cosmetic adjuvants.

The emulsion according to the invention moreover has good sensoryqualities, in particular great ease of application, comfort, softness, agood matte effect and good coverage, uniformity and staying power.

The emulsions of the invention comprise an emulsifying system comprisinga specific α,ω-substituted oxyalkylenated silicone.

Throughout the text hereinabove and hereinbelow, the term “silicone” isintended to denote, in accordance with general acceptance, anyorganosilicon polymers or oligomers of linear or cyclic, branched orcrosslinked structure, of variable molecular weight, obtained bypolymerization and/or polycondensation of suitably functionalizedsilanes, and comprising a repetition of main units in which the siliconatoms are connected together via oxygen atoms (siloxane bond≡Si—O—Si≡),optionally substituted hydrocarbon-based radicals being linked directlyvia a carbon atom onto the said silicon atoms. The hydrocarbon-basedradicals which are most common are alkyl radicals, especially C₁-C₁₀alkyl radicals and in particular methyl, fluoroalkyl radicals, arylradicals and in particular phenyl. They can be substituted, for example,with C₁-C₄₀ ester or ether groups or C₇-C₆₀ aralkyl groups.

Thus, the α,ω-substituted oxyalkylene silicone which may be usedaccording to the invention is an organosilicon polymer as defined above,of linear structure, substituted at the two ends of the main chain withoxyalkylene groups connected to the Si atoms via a hydrocarbon-basedgroup.

The α,ω-substituted oxyalkylenated silicone which can be used accordingto the invention corresponds to the general formula (I) below:

in which: R=—(CH₂)_(p)O—(C₂H₄O)_(x)(C₃H₆O)_(y)R¹

where: R¹ represents H, CH₃ or CH₂CH₃,

p is an integer ranging from 1 to 5, x ranges from 1 to 100 and y rangesfrom 1 to 50,

it being possible for the units (C₂H₄O) and (C₃H₆O) to be distributedrandomly or in blocks,

the R² radicals represent a C₁-C₃ alkyl radical or a phenyl radical, and

5≦m≦300.

Preferably, the α,ω-substituted oxyalkylenated silicone used accordingto the present invention corresponds to the general formula (I) forwhich all of the R² radicals are methyl radicals and:

p ranges from 2 to 4,

x ranges from 3 to 100,

m ranges from 50 to 200.

Preferably also, the average molecular weight of R ranges from 800 to2600.

Preferably, the weight ratio of the C₂H₄O units relative to the C₃H₆Ounits ranges from 100:10 to 20:80.

Preferably, this ratio is about 42/58.

Preferably also, R¹ is a methyl group.

Even more preferably, the emulsion according to the invention comprisesthe α,ω oxyalkylenated silicone of the following formula:

in which:

m=100,

R=(CH₂)₃—O—(C₂H₄O)_(x)—(C₃H₆O)_(y)—CH₃, where x ranges from 3 to 100 andy ranges from 1 to 50, the weight ratio of C₂H₄O units to C₃H₆O unitsbeing about 42/58, the average molecular weight of R ranging from 800 to1000.

The α,ω-substituted oxyalkylenated silicone as defined above is usedaccording to the invention in a proportion ranging from 0.1 to 30%,preferably from 0.5 to 10%, by weight relative to the total weight ofthe emulsion.

Among the commercial products which can contain all or some of theα,ω-substituted oxyalkylenated silicones which may be used according tothe invention as emulsifier are those sold under the names “Abil EM 97”by the company Goldschmidt or “KF 6009”, “X22-4350”, “X22-4349” or “KF6008” by the company Shin Etsu.

The emulsifying system in the emulsions according to the invention alsocomprises a co-surfactant chosen from glycol mono- and/or diesters andglyceryl mono-, di- and/or triesters, and/or mixtures thereof.

Preferably, the co-surfactant has a HLB (Hydrophilic-Lipophilic Balance)of 7 or less.

Preferably, this co-surfactant is chosen from fatty acid esters ofglycol and/or of glycerol such as glyceryl stearate, acetylated ethyleneglycol stearate and isostearyl diglyceryl succinate.

Co-surfactants of this type are, for example the product sold by thecompany Hüls under the name “Imwitor 780K”, which is an isostearyldiglyceryl succinate.

Mention may also be made of the product sold under the name “Unitwix” bythe company United Guardian, which is a product comprising a mixture offatty acid esters of glycerol and of glycol in a ratio of between 75/25and 95/5% by weight, the said fatty acids being C₁₆-C₃₆, at least 50% ofthe said fatty acids being Cl₈-C_(22.)

Preferably, the co-surfactant is present in the emulsions and thecompositions according to the invention in a proportion ranging from0.05% to 10%, more preferably in a proportion ranging from 0.2% to 5%.

The fatty phase of the emulsions according to the invention comprises atleast one volatile or non-volatile silicone oil.

The silicone oil which may be used according to the invention may be alinear, optionally functionalized or cyclic polydiorganosiloxane or anoptionally crosslinked organopolysiloxane, or a mixture thereof.

The optionally functionalized linear polydiorganosiloxanes which may beused according to the invention correspond to the following generalformula:

in which:

X is —CH₃ or OH and

n is an integer ranging from 0 to 2000.

Among these, mention will be made in particular of the products soldunder the name “AK” by the company Wacker, “SF” by the company GeneralElectric and “Abil” by the company Goldschmidt, such as the product“Abil 10”.

As cyclic polydiorganosiloxanes according to the invention, it ispossible to use, alone or as a mixture, cyclomethicones of formula:

in which:

n is an integer from 3 to 8.

Among the cyclomethicones which are particularly preferred, mention willbe made of cyclotetradimethylsiloxane (n=4), cyclopentadimethylsiloxane(n=5) and cyclohexadimethylsiloxane (n=6).

It is possible in particular to use the products sold under the names“DC Fluid 244”, “DC Fluid 245”, “DC Fluid 344” and “DC Fluid 345” by thecompany Dow Corning.

Other cyclomethicones which may be used according to the invention arethose sold under the names “Abil K4” by the company Goldschmidt;“Silbione 70045 V2” and “Silbione Oil 70045 V5” by the companyRhone-Poulenc; as well as “Volatile Silicone 7158” and “VolatileSilicone 7207” by the company Union Carbide.

Preferably, volatile silicone oils, including cyclomethicones, are used.

As indicated above, the silicone oil used according to the invention ispreferably present in a proportion of at least 5%, and preferablyranging from 25 to 45%, by weight relative to the total weight of theemulsion.

The compositions of the invention may also comprise other siliconecompounds.

Among these silicone compounds are poly(C₁-C₂₀)alkylsiloxanes, includingphenylsilicone oils, as well as silicone gums and silicone waxes.

The silicone gums which may be used in the composition of the inventionmay be polysiloxanes with a high molecular mass, from about 200,000 toabout 1,000,000, and with a dynamic viscosity of greater than 500,000mPa·s. They may be used alone or as a mixture with a solvent such as apolydimethylsiloxane or polyphenylsiloxane oil, or a cyclomethicone.

The gums may be present in an amount up to 5% by weight of activematerial in the final composition, preferably up to 1%.

The silicone waxes which may be used in the composition according to theinvention may be substituted linear polysiloxanes, for example,polyether silicone waxes and alkyldimethicones or alkoxydimethiconescontaining from 16 to 45 carbon atoms. These silicone waxes may bepresent in a proportion ranging from 0 to 15% by weight in the finalcomposition, preferably in a proportion ranging from 2 to 10%.

The emulsions according to the invention may also comprise siliconeresins comprising a combination of the units R₃SiO_(1/2), R₂SiO_(2/2),RSiO_(3/2) and SiO_(4/2).

The compositions according to the invention may also comprisenon-silicone fatty substances, including pasty fatty substances, gumsand waxes of plant, mineral, animal or synthetic origin.

The pasty fatty compounds may be defined with the aid of at least one ofthe following physicochemical properties:

having a viscosity ranging from 0.1 to 40 Pa·s (1 to 400 poises),measured at 40° C. with a Contraves TV rotary viscometer fitted with anMS-r3 or MS-r4 rotor at a frequency of 60 Hz, or

having a melting point ranging from 25 to 70° C., preferably from 25 to55° C.

Preferred non-silicone waxes which may be used in the invention arewaxes of animal origin, such as lanolin, beeswax, spermaceti, lanolinderivatives such as lanolin alcohols and hydrogenated, hydroxylated oracetylated lanolin, lanolin fatty acids and acetylated lanolin alcohol;waxes of plant origin, such as carnauba wax, candelilla wax, kapok wax,ouricury wax, rice wax, hydrogenated jojoba wax, alfalfa wax, Japan wax,cork fibre waxes or sugar cane wax, or even cocoa butter; mineral waxes,for example paraffin wax, montan wax, lignite wax, petrolatum wax,petroleum jelly wax or microcrystalline waxes, ceresin or ozokerite;synthetic waxes, such as polyethylene waxes, the waxes obtained byFischer-Tropsch synthesis and linear esters resulting from the reactionof a saturated C₁₀ to C₄₀ carboxylic acid and a saturated C₁₀ to C₄₀alcohol, such as myristyl myristate. Cetyl alcohol, stearyl alcohol,calcium lanolates or stearates, castor oil, palm oil, coconut oil,sunflower oil or hydrogenated coconut oil may also be used.

The fatty phase of the W/O emulsion according to the invention maycomprise one or more hydrocarbon-based oil(s) in a proportion which canbe up to 40% by weight relative to the total weight of the fatty phaseof the emulsion.

A preferred hydrocarbon-based oil is any fluid oil (or mixture of oils)which is stable at the usual temperature at which the cosmetic,pharmaceutical or hygiene products are used, such as oils of plant,animal, mineral or synthetic origin, fluoro oils and triglycerides ofC₁₂-C₁₈ fatty acids.

Preferred oils of plant or animal origin, which may be modified orunmodified are, for example, sweet almond oil, avocado oil, castor oil,olive oil, jojoba oil, sunflower oil, wheat germ oil, sesame oil,groundnut oil, grape seed oil, soybean oil, rapeseed oil, safflower oil,coconut oil, corn oil, hazelnut oil, karite butter, palm oil, (apricot)kernel oil or beauty-leaf oil.

Preferred oils of mineral origin are, for example, liquid paraffin.

Preferred synthetic oils are, in particular, volatile or non-volatileisoparaffins and polyisobutenes.

These fatty substances may be chosen in particular by a person skilledin the art so as to prepare a composition having the desired properties,for example in terms of consistency or texture. They are preferably usedat a content of less than or equal to 7% by weight relative to the totalweight of the emulsion, in order to preserve the advantageous propertiesof the emulsion used according to the invention.

Other liposoluble adjuvants which may be incorporated into the fattyphase are lipophilic UV screening agents, lipophilic vitamins,antioxidants, fragrances and ceramides.

The aqueous phase of the emulsion according to the invention maycomprise water or a floral water such as cornflower water.

In addition, the aqueous phase may comprise from 0% to 14% by weight,relative to the total weight of the aqueous phase, of a lower C₂-C₆monoalcohol and/or a polyol such as glycerol, butylene glycol, isopreneglycol or propylene glycol.

The aqueous phase may also contain adjuvants commonly used in cosmeticW/O emulsions, for example, lubricants, moisturizers such as glyceroland propylene glycol, trace elements, hydrophilic UV screening agentsand polysaccharides, as well as electrolytes such as NaCl or MgSO₄. Theaqueous phase may also comprise active principles such as plantextracts, bacterial extracts, proteins or protein hydrolysates, and inparticular hydrolysates of collagen or of elastin.

These active principles may be present in a proportion ranging from 1 to15%.

Depending on the texture desired for the emulsion according to theinvention, the proportion of the dispersed aqueous phase may range from35% to 80%.

In general, the emulsion according to the invention may comprise from30% to 55% by weight of fatty phase, from 5% to 12% by weight ofsurfactant, and from 35% to 75% by weight of aqueous phase.

In addition, the emulsion according to the invention may comprise one ormore co-surfactants and one or more thickeners in concentrationspreferably ranging from 0 to 6% by weight, relative to the total weightof the emulsion.

The thickener may be chosen from modified clays such as modifiedmagnesium silicate (bentone gel VS38 from Rheox) or hectorite modifiedwith distearyldimethylammonium chloride (bentone 38 CE from Rheox).

Advantageously, the emulsion according to the invention is substantiallyfree of thickener.

The emulsion according to the invention may also comprise pearlescentagents, pigments and/or fillers usually used in cosmetic compositions.

The pigments may be present in the emulsion in a proportion ranging from0 to 20% by weight, relative to the total weight of the emulsion, andpreferably in a proportion ranging from 2 to 15%. They may be white orcoloured, and inorganic and/or organic. Preferred inorganic pigments aretitanium dioxide, zirconium dioxide or cerium dioxide, as well as zincoxide, iron oxide or chromium oxide, ferric blue, pearlescent agentssuch as mica coated with titanium oxide, with iron oxide, with naturalpigment or with bismuth oxychloride, as well as coloured titanium mica.Preferred organic pigments are, for example, carbon black, and barium,strontium, calcium and aluminium lakes. The pigments may also have ahydrophobic surface or may be treated so as to make their surfacehydrophobic; this treatment may be carried out according to the methodsknown to those skilled in the art; in particular, the pigments may becoated with silicone compounds such as PDMSs and/or with polymers, inparticular polyethylenes and/or amino acids.

Preferred coated pigments are, for example, the pigments sold under thename “Covasil” by the company Wacker (pigments containing triisostearyltitanate).

The pigments thus coated can be incorporated into the emulsion accordingto the invention in a proportion ranging from 0.1 to 15% by weightrelative to the total weight of the emulsion.

The fillers, which may be present in the emulsion in a proportionranging from 0 to 20% by weight relative to the total weight of theemulsion, preferably from 0 to 10%, may be mineral or synthetic, andlamellar or non-lamellar. Preferred fillers are, for example, talc,mica, silica, kaolin, Teflon, starch, natural mother-of-pearl, boronnitride, microspheres such as Expancel (Nobel Industrie), ormicrosponges such as Polytrap (Dow Corning). Preferably, sphericalfillers which are less than 25 μm in size are used, such as polyethylenepowders, Nylon powders, microbeads of silicone resin (Tospearis fromToshiba) or silica microspheres, it being possible for these fillers tocontribute towards improving the transfer-resistance properties of theemulsions of the invention.

In a preferred form of the invention, the emulsion comprises fillershaving an average particle size equal to 15 microns or less. Preferably,these fillers are non spherical. Preferably, the weight ratio of thefillers to the oils, in the composition applied on the skin and afterevaporation of the volatile oils, is from 30:70 to 50:50. Morepreferably, if n, represents the average refractive index of thetotality of the fillers and if n₂ represents the average refractiveindex of the totality of the oils, then:

0<|n ₁ −n ₂|≦0.3

and preferably,

0<|n ₁ −n ₂|≦0.15.

Thus, it is possible to obtain a foundation comprising very few pigmentsand still concealing the skin microreliefs. This composition showssoft-focus properties, in other words, it gives a blurred effect whichconceals the skin microreliefs.

The emulsion according to the invention may also comprise a film-formingcompound.

Thus the emulsion according to the invention may comprise polymers inaqueous dispersion, such as, for example, acrylic polymers, polyestersand/or polyurethanes in aqueous dispersion. For example, the emulsionmay comprise a vinyl acetate/vinyl p-tert-butylbenzoate/crotonic acidcopolymer as a stabilized, partially neutralized aqueous dispersion.

The emulsion according to the invention may also comprise a dispersionof polymer particles in a non-aqueous medium, as described, for example,in document EP 749,747.

The emulsion according to the invention may also comprise acosmetically, pharmaceutically or hygienically acceptable medium. Inthis case, it may comprise any additive usually used in the field ofcosmetics, pharmaceuticals or hygiene, such as antioxidants, dyes,fragrances, essential oils, preserving agents, cosmetic active agents,moisturizers, vitamins, sphingolipids, liposoluble polymers, inparticular hydrocarbon-based polymers, such as polybutene,polyalkylenes, polyacrylates and silicone polymers which are compatiblewith the fatty substances.

These additives may be present in the composition in a proportionranging from 0 to 10% by weight.

Needless to say, a person skilled in the art will take care to selectoptional complementary compounds, and/or the amount thereof, such thatthe advantageous properties of the composition according to theinvention are not, or are not substantially, adversely affected by theaddition envisaged.

The emulsions according to the invention may be in the form of acosmetic product, and in particular in the form of a care product forthe body and/or the face and/or the scalp, or alternatively a make-upproduct, in particular a foundation,a blusher, an eyeshadow, aneyeliner, a mascara or a lipstick.

They may also be in non-dyed form, optionally containing cosmetic activeagents. The emulsion according to the invention may be in the form of athickened emulsion, a fluid emulsion, a cream, a milk or a serum, whichmay be used as a care product or an antisun product.

Preferably, the emulsions according to the invention are in the form ofa fluid.

The process for preparing the emulsions according to the inventioncomprised: (a) in a first stage, heating the fatty phase containing theemulsifying system up to a temperature which is sufficient to melt allof the constituents, preferably a temperature ranging from 60 to 85° C.,and then incorporating the optional additional liposoluble adjuvants,and (b) in a second stage, after cooling the fatty phase to atemperature ranging from 40 to 60° C., adding the aqueous phase, broughtto the same temperature, to the fatty phase with slow gentle stirring,and then, when the temperature has returned to about 25° C., subjectingthe preparation to vigorous stirring.

This second step may also be carried out by addition of the aqueousphase to the fatty phase with vigorous stirring, the aqueous phase beingbrought to the same temperature as the fatty phase.

Several examples of cosmetic compositions in the form of W/O emulsionswill now be given for illustrative purposes. In the examples whichfollow, the amounts are given as a percentage by weight relative to thetotal weight of the composition.

COMPARATIVE EXAMPLE

The Inventors prepared the following two emulsions A and B with similardynamic viscosities (˜500 mPa·s (500 cps) at T°=25° C.). Theseviscosities were measured with an RM180 Rheomat viscometer (RheometricScientific) with spindle No. 2, at a temperature of 25° C. and at ashear rate of 200 s⁻¹, at time t=10 minutes.

Emulsion A (in accordance with the invention):

α, ω-substituted oxypropylenated oxyethylenated 6%silicone/cyclomethicone mixture (85/15) sold under the trade name “AbilEM 97” by the company Goldschmidt isostearyl diglyceryl succinate soldunder the trade 2% name “Imwitor 780 K” by the company Hülscyclomethicone 25% isododecane 4.55% pigment 10% Nylon powder 8% vinylacetate/vinyl p-tert-butylbenzoate/crotonic acid 20% copolymer as astabilized, partially neutralized aqueous dispersion diisopropyl adipate1% water qs 100%

Emulsion B (comparative):

silicone containing pendant alkyl, oxyethylene and 9% oxypropylenegroups in a mixture of polyglyceryl 4-isostearate and hexyl laurate,sold under the trade name “Abil WE 09” by the company Goldschmidtmixture of acetylated glycol stearate and tristearine 0.5% sold underthe trade name “Unitwix” by the company Guardian cyclomethicone 25%diphenyl dimethicone 6% isododecane 4.55% hectorite 4% pigment 10% Nylonpowder 8% vinyl acetate/vinyl p-tert-butyl benzoate/crotonic acid 20%copolymer as a stabilized, partially neutralized aqueous dispersiondiisopropyl adipate 1% water qs 100%

These emulsions were obtained according to the following preparationprocess:

the pigments were predispersed in some of the cyclomethicone.

The rest of the oil was homogenized with the surfactants (at atemperature ranging from 40 to 50° C. for emulsion B, without heatingfor emulsion A).

The mixture was left to cool. The pigments and the Nylon powder wereadded to this mixture (and the modified hectorite preswollen in a smallamount of isododecane, for emulsion B).

All of the aqueous phase was added to the above fatty phase, at firstwith slow stirring, and then with vigorous stirring for 10 minutes.

The copolymer and the diisopropyl adipate were added, with slowstirring.

These two foundations have a creamy, light, soft texture. They are easyto apply to the skin and give the skin a velvety appearance. They feelvery softny. They are comfortable to wear.

1) Evaluation of the Stability:

Emulsion A according to the invention has better stability after 1 monthat T°=45° C. than emulsion B (for emulsion B, considerable release ofoil at the surface of the emulsion and many signs of breakdown of theemulsion and of reaggregation of the pigments are observed bymicroscope), this being the case even in the absence of stabilizingcompounds such as the silicone gum (diphenyl dimethicone) and thehectorite which are present in emulsion B.

2) Evaluation of the Transfer Resistance:

The Inventors evaluated the transfer resistance of these twocompositions in the following way: emulsions A and B were appliedcomparatively per half-neck to a panel of 6 individuals. The productswere then left to dry for 10 minutes. Neck bands were then applied for30 minutes to each half-neck.

The results obtained are collated in the following table:

Emulsion A Emulsion B Transfer (invention) (comparative) None 0 Traces 1Traces + 2 Slight 3 3 Slight + 4 1 1 Moderate 5 2 4 Moderate + 6 1 Large7 SCORE (average) 3.8 5

It emerges clearly from the above table that the composition accordingto the invention which comprises, as emulsifying system, a combinationof α,ω-oxyalkylenated silicone with a glyceryl ester, transfers lessthan an emulsion of the prior art, which comprises a dimethiconecopolyol; not in accordance with that of the invention with a glycerylester.

Composition Example

The Inventors made the following composition:

lipophilic coated pigments 3% talc having an average particle size ofless than 15 microns 8% magnesium sulfate 0.7% α-ω-substitutedoxypropylenated oxyethylenated 6% silicone/cyclomethicone mixture(85/15) sold under the trade name “Abil EM 97” by the companyGoldschmidt isostearyl diglyceryl succinate sold under the trade name 2%“Imwitor 780 K” by the company Hüls cyclomethicone 25%polydimethylsiloxane 4% isododecane 4.5% preservative qs water qs 100%

This composition, although containing very few pigments, concealsadvantageously the skin microreliefs.

What is claimed is:
 1. A water-in-oil emulsion, comprising an aqueousphase and a fatty phase comprising at least one silicone oil, saidemulsion comprising an emulsifying system comprising at least oneα,ω-substituted oxyalkenylated silicone of formula (I):

in which: R=—(CH₂)_(p)O—(C₂H₄O)_(x)(C₃H₆O)_(y)R¹ where: R¹ represents H,CH₃ or CH₂CH₃, p is an integer ranging from 1 to 5, x ranges from 1 to100 and y ranges from 1 to 50, the units (C₂H₄O) and (C₃H₆O) beingdistributed randomly or in blocks, the R² radicals represent a C₁-C₃alkyl radical or a phenyl radical, 5≦m≦300, and at least oneco-surfactant chosen from glycol monoesters, glycol diesters, glycerylmonoesters, glyceryl diesters, and glyceryl triesters, with the provisothat the glyceryl triesters are not chosen from glyceryl trioctanoate.2. The emulsion according to claim 1, wherein said R² radicals are allmethyl radicals and: p ranges from 2 to 4, x ranges from 3 to 100, mranges from 50 to
 200. 3. The emulsion according to claim 1, wherein theaverage molecular weight of R ranges from 800 to
 2600. 4. The emulsionaccording to claim 1, wherein the weight ratio of the C₂H₄O unitsrelative to the C₃H₆O units ranges from 100:10 to 20:80.
 5. The emulsionaccording to claim 4, wherein said weight ratio is about 42/58.
 6. Theemulsion according to claim 1, wherein the R¹ is a methyl group.
 7. Theemulsion according to claim 1, wherein said oxyalkylenated siliconecorresponds to the following formula:

in which: m=100, R=(CH₂)₃—O—(C₂H₄O)_(x)—(C₃H₆O)_(y)—CH₃, where x rangesfrom 3 to 100 and y ranges 1 to 50, the weight ratio of C₂H₄O units toC₃H₆O units being about 42/58, the average molecular weight of R rangingfrom 800 to
 1000. 8. The emulsion according to claim 1, wherein saidoxyalkylenated silicone is present in the emulsion in a proportionranging from 0.1 to 30% by weight relative to the total weight of theemulsion.
 9. The emulsion according to claim 8, wherein saidoxyalkylenated silicone is present in the emulsion in a proportionranging from 0.5 to 10%.
 10. The emulsion according to claim 1, whereinsaid co-surfactant is chosen from fatty acid esters of glycol and ofglycerol.
 11. The emulsion according to claim 10, wherein said fattyacid esters of glycol or of glycerol are chosen from glyceryl stearate,acetylated ethylene glycol stearate and isostearyl diglyceryl succinate.12. The emulsion according to claim 11, wherein said co-surfactant isisostearyl glyceryl succinate.
 13. The emulsion according to claim 1,wherein said co-surfactant is a mixture of fatty acid esters of glyceroland of glycol in a ratio ranging from 75/25 to 95/5% by weight, the saidfatty acids being C₁₆-C₃₆, and at least 50% of the said fatty acidsbeing C₁₈-C₂₂.
 14. The emulsion according to claim 1, wherein saidco-surfactant is present in a proportion ranging from 0.05% to 10% byweight, relative to the total weight of the emulsion.
 15. The emulsionaccording to claim 14, wherein said co-surfactant is present in aproportion ranging from 0.2% to 5%.
 16. The emulsion according to claim1, wherein said at least one silicone oil is chosen from optionallyfunctionalized linear polydiorganosiloxanes, cyclicpolydiorganosiloxanes, and optionally crosslinked organopolysiloxanes.17. The emulsion according to claim 16, wherein saidpolydiorganosiloxanes correspond to the following formula:

in which: X is —CH₃ or OH, and n is an integer ranging from 0 to 2000.18. The emulsion according to claim 16, wherein said cyclicpolydiorganosiloxanes are chosen from cyclomethicones and mixtures ofcyclomethicones corresponding to the following formula:

in which: n is an integer from 3 to
 8. 19. The emulsion according toclaim 18, wherein said cyclomethicones are chosen fromcyclotetradimethylsiloxane (n=4), cyclopentadimethylsiloxane (n=5) andcyclohexadimethylsiloxane (n=6).
 20. The emulsion according to claim 16,wherein said at least one silicone oil is chosen from cyclicpolydiorganosiloxanes.
 21. The emulsion according to claim 16, whereinsaid at least one silicone oil is present in a proportion of at least 5%by weight relative to the total weight of the emulsion.
 22. The emulsionaccording to claim 21, wherein said at least one silicone oil is presentin a proportion ranging from 25 to 45%.
 23. The emulsion according toclaim 1, wherein said emulsion further comprises silicone compounds,different from said at least one silicone oil as defined in claim 1,chosen from poly(C₁-C₂₀)alkylsiloxanes, silicone gums and siliconewaxes.
 24. The emulsion according to claim 23, wherein said siliconegums have a molecular mass ranging from about 200,000 to about1,000,000, and with a dynamic viscosity of greater than 500,000 mPa·s.25. The emulsion according to claim 23, wherein said silicone gums arepresent in an amount up to 5% by weight of active material in the finalemulsion.
 26. The emulsion according to claim 23, wherein said siliconegums are present in an amount up to 1%.
 27. The emulsion according toclaim 23, wherein said silicone waxes are substituted linearpolysiloxanes.
 28. The emulsion according to claim 27, wherein saidsubstituted linear polysiloxanes are chosen from polyether siliconewaxes, alkyldimethicones containing from 16 to 45 carbon atoms, andalkoxydimethicones containing from 16 to 45 carbon atoms.
 29. Theemulsion according to claim 23, wherein said silicone waxes are presentin a proportion up to 15% by weight of the final emulsion.
 30. Theemulsion according to claim 29, wherein said silicone waxes are presentin an amount ranging from 2 to 10%.
 31. The emulsion according to claim1, wherein said emulsion further comprises at least one silicone resincomprising a combination of the units R₃SiO_(1/2), R₂SiO_(2/2),RSiO_(3/2), and SiO_(4/2).
 32. The emulsion according to claim 1,wherein said emulsion further comprises at least one non-silicone fattysubstance chosen from pasty fatty substances, gums, waxes of plantorigin, waxes of mineral origin, waxes of animal origin, waxes ofsynthetic origin, oils of plant origin, oils of mineral origin, oils ofanimal origin, and oils of synthetic origin.
 33. The emulsion accordingto claim 1, wherein said fatty phase comprises at least onehydrocarbon-based oil in an amount up to 40% by weight relative to thetotal weight of the fatty phase of the emulsion.
 34. The emulsionaccording to claim 1, wherein said fatty phase further compriseslipophilic adjuvants chosen from lipophilic UV screening agents,lipophilic vitamins, antioxidants, fragrances and ceramides.
 35. Theemulsion according to claim 1, wherein said aqueous phase compriseswater or a floral water.
 36. The emulsion according to claim 1, whereinsaid aqueous phase comprises from 0 to 14% by weight, relative to thetotal weight of the aqueous phase, a lower C₂-C₆ monoalcohol or apolyol.
 37. The emulsion according to claim 1, wherein said aqueousphase further comprises adjuvants and active principles.
 38. Theemulsion according to claim 37, wherein said active principles arepresent in a proportion ranging from 1 to 15%.
 39. The emulsionaccording to claim 1, wherein said aqueous phase is present in an amountranging from 35 to 80% of the total weight of the emulsion.
 40. Theemulsion according to claim 1, wherein said emulsion comprises from 30to 55% by weight of fatty phase, from 5 to 12% by weight of surfactant,and from 35 to 75% by weight of aqueous phase.
 41. The emulsionaccording to claim 1, wherein said emulsion further comprises at leastone co-surfactant different from said at least one co-surfactant asdefined in claim
 1. 42. The emulsion according to claim 1, wherein saidemulsion further comprises a particulate phase which comprises at leastone ingredient selected from pigments, pearlescent agents, and fillers.43. The emulsion according to claim 42, wherein said at least onepigment is present in an amount up to 20% by weight relative to thetotal weight of the emulsion.
 44. The emulsion according to claim 43,wherein said at least one pigment is present in an amount ranging from 2to 15%.
 45. The emulsion according to claim 42, wherein said at leastone filler is chosen from talc, mica, silica, kaolin, Teflon, starch,natural mother-of-pearl, boron nitride, microspheres, microsponges,polyethylene powders, Nylon powders, microbeads of silicone resin andsilica microspheres.
 46. The emulsion according to claim 42, whereinsaid at least one filler is present in an amount up to 20% by weightrelative to the total weight of the emulsion.
 47. The emulsion accordingto claim 46, wherein said at least one filler is present in an amount upto 10%.
 48. The emulsion according to claim 42, wherein said at leastone filler has an average particle size of 15 microns or less.
 49. Theemulsion according to claim 42, wherein said at least one filler is nonspherical.
 50. The emulsion according to claim 42, wherein the weightratio of said at least one filler to said at least one silicone oil, inthe emulsion applied on skin and after evaporation of any volatile oilsin said emulsion, ranges from 30:70 to 50:50.
 51. The emulsion accordingto claim 42, wherein n₁ represents the average refractive index of thetotality of said at least one filler and n₂ represents the averagerefractive index of the totality of said at least one silicone oils and0<|n ₁ −n ₂|≦0.3.
 52. The emulsion according to claim 51, wherein 0<|n ₁−n ₂|≦0.15.
 53. The emulsion according to claim 1, wherein said emulsionfurther comprises a film-forming compound.
 54. The emulsion according toclaim 1, wherein said emulsion further comprises a cosmetically,pharmaceutically or hygienically acceptable medium.
 55. The emulsionaccording to claim 1, wherein said emulsion further comprises additivespresent in a proportion up to 10% by weight relative to the total weightof the emulsion.
 56. A composition for cosmetic, dermatological,pharmaceutical or hygiene use, wherein said composition comprises anemulsion according to claim
 1. 57. The composition according to claim56, wherein said composition is in the form of a cosmetic or careproduct for the body and/or the face and/or the scalp, or a make-upproduct, in the form of a foundation, a blusher, an eyeshadow, aneyeliner, a mascara or a lipstick.
 58. The composition according toclaim 57, wherein said composition is in the form of a thickenedemulsion, a fluid emulsion, a cream, a milk or a serum.
 59. Thecomposition according to claim 58, wherein said composition is in theform of a fluid emulsion.
 60. A process for the non-therapeutictreatment of the skin and/or keratin fibres, comprising applying aneffective amount of an emulsion according to claim 1 and/or acomposition containing an emulsion according to claim 1, to said skinand/or said keratin fibres.
 61. A process for preventing or reducing thetransfer or migration of a cosmetic, hygiene or pharmaceuticalcomposition, comprising introducing into said composition an effectiveamount of an emulsifying system according to claim
 1. 62. A process forreducing or preventing the transfer of a cosmetic, dermatological,hygiene and/or pharmaceutical composition, for the skin, mucousmembranes, semi-mucous membranes and/or keratin fibres, said processcomprising introducing an emulsifying system according to claim 1, intosaid composition.